Showing 3 results for Farahani
Dr. Hassan Feshki Farahani, Dr. Mahmood Hosseini Aliabadi, Dr. Shahram Javadi, Mr. Siamak Porkar,
Volume 13, Issue 4 (Vol.13 No.4 2017)
Abstract
In this paper a new topology is introduced for three-phase inverter that includes a multi-level module, a three-phase inverter bridge and middle levels selection unit. The main advantage of proposed topology is using fewer switches and diodes to reach the maximum level of output voltage. The structure consists of a single-phase multilevel module; three bidirectional switches and a three-phase inverter bridge. The other capability of this structure is increasing of two level of output voltage just by adding a bidirectional switch and a low voltage capacitor. In this paper is proposed the switching sequences to access for any number of output voltage levels. Furthermore, the amplitude of the harmonic and THD of the proposed structure are compared with other structures. To demonstrate the effectiveness of the proposed method, a sample of 11-level three-phase inverter is designed and is simulated using Simulink toolbox of MATLAB software and the obtained results have been evaluated.
Dr Ahmad Dehghanzadehsoraki, Dr Gholamreza Farahani, Dr Mostafa Rajabi Mashhadi,
Volume 16, Issue 2 (JIAEEE Vol.16 No.2 2019)
Abstract
In this paper, using Thevenin’s theorem and also nonlinear Lambert W function, a novel two-diode model of photovoltaic cells is presented in mathematical explicit manner. In comparison with existing explicit models in the literature which are valid exclusively for n2=n1 and n2=2n1, this model includes a wide range of silicon-based cells with arbitrary diodes ideality factors. Acquiring regulating parameter (a) of the proposed model, its suitability to conform the real data is verified at standard test condition with maximum error of 10-5. Moreover, recreating the changes in weather condition, the proposed model performance is validated for irradiations between 50 up to 1100 Watt/m2. Finally, with series and parallel configuration of the PV cells and analytic derivation of maximum power point, the two-diode model for PV modules is simulated in SimPowerSystems of MATLAB software for research and engineering applications.
Mahdi Mazidabadi Farahanifarahani, Dr. Jalil Mazloum, Dr. Payman Nayebi,
Volume 19, Issue 2 (JIAEEE Vol.19 No.2 2022)
Abstract
Cognitive radio is well known as an ultra-wideband communication system that intelligently optimizes the available frequency spectrum by implementing the dynamic spectrum monitoring method. The receiver of such a system requires an ultra-wideband low noise amplifier (from 50 MHz to 10 GHz). In this work, a low power ultra-wideband low noise amplifier is proposed by quasi-differential structure and active inductors. Using active circuits as inductors, in addition to expanding the amplifier bandwidth and reducing the chip area, have an inherent gain and due to their high quality factor, have the ability to adjust the inductance and frequency. In addition, the quasi-differential structure increases the transconductance of transistors and reduces both power consumption and noise figure of this circuit. The simulation results in a 0.18 µm CMOS process show that the proposed LNA achieved NF changes 3-7 dB and input matching less than -10 dB in the 0.05-10 GHz band. The voltage gain changes from 16.5-19 dB and third-order intercept point is -6.7 dBm. The power consumption of the main circuit is 1.98 mW with 1.8 V power supply.
